So I’ve been looking at AIO handling in f_fs and either I’m stupid or
the code is broken. Here’s part of ffs_user_copy_worker:
int ret = io_data->req->status ? io_data->req->status :
io_data->req->actual;
if (io_data->read && ret > 0) {
use_mm(io_data->mm);
ret = copy_to_iter(io_data->buf, ret, &io_data->data);
if (iov_iter_count(&io_data->data))
ret = -EFAULT;
unuse_mm(io_data->mm);
}
First of all, shouldn’t the copy_to_iter invocation be:
if (copy_to_iter(io_data->buf, ret, &io_data->data))
ret = -EFAULT;
Second of all, if the request reads fewer bytes than user requested,
iov_iter_count(…) will be non-zero (namely it will be the difference
between user’s buffer size and data read). This should not result in
EFAULT though.
So, am I going crazy? Or does this need to be fixed as well?
--
Best regards
ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ
«If at first you don’t succeed, give up skydiving»
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